A dehumidifier’s capacity rating is a number without a home until you know the conditions it was measured at. Two units can both be described as “70 pint” and remove very different amounts of water from the same basement, because water removal depends on the air entering the unit — its temperature and its relative humidity.
This is the single most common sizing error we see in distributor submittals, and it is entirely avoidable. Read the table, not the headline.
What PPD means
PPD is pints per day — the mass of water the unit removes in 24 hours, expressed as a volume of liquid. It is the standard way to describe dehumidifier capacity in North America, and it is always conditional. The rating is established at a defined entering air condition.
Three conditions are conventionally published, and they tell you how the unit will behave in three different situations:
| Entering air condition | What it represents | Why it matters |
|---|---|---|
| 80°F / 60% RH | The standard rating condition used for regulatory reporting | Compare models on this column |
| 86°F / 80% RH | A hot, humid summer basement or crawlspace | The “capacity” most buyers picture |
| 90°F / 90% RH | Extreme humidity — a wet crawlspace or a flooded space | The upper end of the unit’s output |
The spread between these three rows is not a marketing trick. It is physics. A refrigerant dehumidifier moves moisture by condensing it on a cold coil, and the colder and drier the entering air, the less water it can pull out. A unit rated high at 86°F / 80% RH will remove appreciably less at 80°F / 60% RH, and less again in a cool basement in shoulder season.
So the correct question is never “how many pints is it?” but “how many pints at the condition this space will actually present?”
Reading our own table
Our four models, taken directly from the 2026 catalogue, illustrate the point. All four are 120V/60Hz, use R-32, and carry an LED display.
| Model | Airflow | 86°F / 80% RH | 80°F / 60% RH | 90°F / 90% RH | Power | Charge | Weight |
|---|---|---|---|---|---|---|---|
| PA-HD70R32 | 280 CFM | 100 PPD | 70 PPD | 135 PPD | 750 W | R-32 / 9.9 oz | 55 lb |
| PA-WH70R32 | 170 CFM | 100 PPD | 70 PPD | 140 PPD | 490 W | R-32 / 13.6 oz | 65 lb |
| PA-HD100R32 | 250 CFM | 165 PPD | 103 PPD | 203 PPD | 780 W | R-32 / 10.9 oz | 70 lb |
| PA-WH95R32 | 315 CFM | 173 PPD | 95 PPD | 210 PPD | 640 W | R-32 / 17.6 oz | 87 lb |
One caveat on the first two rows. The catalogue publishes two 70-pint models (PA-HD70R32 and PA-WH70R32) with the same 70 PPD rating at 80°F / 60% RH but different airflow, charge and weight. Which physical row belongs to which of those two model codes is confirmed per model on the submittal sheet — take the airflow and charge figures for your specific model from there rather than assuming the order above.
Read across a row and you can see the penalty for a drier space: the PA-WH95R32 removes 173 pints a day in a hot, humid basement and 95 pints a day at 80°F / 60% RH. If you sized that unit on the 173 figure and the space actually sits at the second condition, you have roughly half the capacity you thought you bought.
Read down the columns and you can compare how the four models respond. The two 100-pint models take different routes to that number — one moves less air with a larger charge, one moves more air with a smaller charge — which is exactly why airflow, power draw and weight belong in the table alongside the pints.
The sizing procedure
Work in this order, with instruments rather than assumptions.
- Measure the space. Volume in cubic feet, plus a description of the envelope: is it sealed, is it ventilated with outdoor air, is there exposed earth?
- Measure the entering air condition. Temperature and relative humidity at the point where the dehumidifier will draw its air. This is the number that selects the row of the table.
- Identify the moisture load. Bulk water entry, exposed earth, unsealed crawlspace vents, laundry, and outdoor air introduced by ventilation all add load.
- Establish the target indoor relative humidity, and confirm it with the homeowner or the builder.
- Select the model on the 80°F / 60% RH column for a conditioned-space installation, and on a hotter and more humid column for a crawlspace or a space with outdoor air ingress. Never select on the highest published number.
- Check the airflow against the ducting. A ducted dehumidifier moving 170 to 315 CFM through long, undersized or flexible ducting will not deliver its rated capacity.
- Check the electrical circuit and the drain. All four of our models are 120V/60Hz. The condensate route needs a continuous fall.
- Confirm the refrigerant charge is documented for the installed configuration — per model on the submittal sheet, as required for the labelling of the equipment.
The four installation configurations
The catalogue lists four ways to connect a ducted dehumidifier, and each has a different effect on the air the unit sees.
Main return to main return — the recommended arrangement. Air is drawn from and returned to the return duct. Use it when no supply duct is available. Because it draws mixed house air, the entering condition is the house condition.
Main return to main supply. Air is pulled from the return duct, dehumidified, and returned to the supply plenum.
Dedicated return to main supply, or dedicated return to the air-conditioning return. A dedicated grille draws from a specific space, typically the wettest one, and delivers into the main system.
Inlet and outlet ducted to dedicated grilles. A fully independent, standalone ducted installation, for when the dehumidifier must operate independently of the air handler.
The choice matters for sizing because it determines the entering air condition. A unit drawing from the main return sees mixed, conditioned air. A unit drawing from a dedicated grille in a damp crawlspace sees something closer to the 86°F / 80% RH row.
Cost of operation, evaluated properly
Do not accept a running-cost claim that is not built from the unit’s own power figure and the local electricity rate. What you can do instead:
- Take the power draw in watts from the model table — 490 W for the PA-WH70R32, 780 W for the PA-HD100R32.
- Multiply by the duty cycle the space will actually impose, which is a function of the moisture load you measured in step 3.
- Multiply by the local tariff, and state the assumption on the same page as the number.
A larger unit that runs less of the time can use less energy than a smaller unit that runs continuously — but that conclusion comes from the load calculation, not from a manufacturer’s claim. We publish no comparative energy or cost claims for these units, because in Canada those claims need testing to support them.
Canadian regulatory notes
Whole-home dehumidifiers are defined in Canada’s energy efficiency regulations as dehumidifiers designed to be installed in an air duct, and they are regulated products: there is a minimum energy performance standard, tied to case volume rather than to pints per day, and an energy efficiency report must be filed. If you are importing, confirm with your supplier which models are registered and under whose dealer account before the shipment leaves. Note also that portable and whole-home dehumidifiers are separate regulatory categories — a unit’s pints-per-day figure does not tell you which one it falls into; its intended installation does.
What to send us
Give us the space volume, the measured temperature and relative humidity, whether outdoor air is introduced, the target humidity, the ducting arrangement you intend, and the available electrical circuit. We will select the model and tell you which of the four configurations fits.
Start with the whole-house dehumidifier family page for the model line and configurations, and the indoor air quality solutions hub for how dehumidification is specified alongside filtration and ventilation. If your moisture problem is a winter problem, the fix is usually a different device: see the ERV / HRV family for how heat and moisture recovery ventilators differ. If you need a unit matched to a specific project, send the load data through the RFQ form.